Barometric Pressure (BARO) Sensor
WARNING: This page is about a different car, the 2013 Honda Fit, 2012 Honda Fit, 2011 Honda Fit, 2010 Honda Fit, and 2009 Honda Fit. However, it is still accessible from the selected car via links, so may be relevant.
The BARO sensor is inside the ECM/PCM. It converts atmospheric pressure into a voltage signal that modifies the basic duration of the fuel injection discharge.